Patients with very good prognostic factors (CBF leukemias, WBC < 30 giga/l at diagnosis, 1st CR after one induction course) = arm C: no allogeneic stem cell transplantation in 1st CR; received 2 more courses of intensive consolidation chemotherapy All others patients received an allogeneic transplant For patients aged less than 51 = arm M: upfront myeloablative conditioning regimen For patients aged over 51 and less than 61= arm m: intensive chemotherapy consolidation course.